There was little discussion of who would keep Tag, my brother’s young black Labrador Retriever, after John’s death. Tag was a living connection to John, and though a grief greater than my own was unfathomable, I knew my mother needed him most. She had lost her broad-shouldered, broad-grinned son. She needed Tag, if only to curl up with when death’s demons haunted. Tag and my mother mourned together. During their first year, a solid rap on the door would send Tag into the fullbody wagging frenzy he reserved for his master’s return. In the seconds before rationality reigned, Mom, too, hoped my brother was about to bound into the house. She had hung John’s Carhartt jacket and ratty baseball cap on a hook above his cowboy boots in her mudroom. It deluded her into thinking that he would be coming back from Colorado for Christmas vacation, with another semester of veterinary school under his belt, on the days when denial was her only method of survival.

John and I had often booked the same flight from Denver to Chicago to descend on Mom in unison for the holidays. On this winter morning I sat alone, squeezed between strangers. I dreaded Christmas without John.Uncovering the ornament he had made in first grade or his knit stocking, stretched out from our tradition of flooding each other with gag gifts, promised to reignite anguish that would feel new and raw all over again. At least I had Tag to look forward to. I couldn’t wait to see that dog.

I was approaching our prearranged meeting place outside O’Hare when I saw them—the unmistakable combination of my stylish mother behind the wheel and a slobbering, yet regal, Tag, straining out the back-seat window.My mom and I greeted each other cautiously, not out of animosity, but restraint. We instinctively knew that if we held each other’s gaze, the sorrow of another holiday without John would overwhelm our weak levee.

“I’ll sit in back with Tag,” I said in a desperate attempt to throw sandbags between our grief.“How’s my boy?” I asked into his eyes while ruffling his ears and scratching him under the collar, where he liked it best. As we pulled away from the airport, Tag straddled my lap to resume his position at the window.Breathing his freshly shampooed scent, I rested my head on his side and hid my burning eyes from Mom’s glances in the rearview mirror.

Despite the lapses between visits to my mother’s house, Tag and I were inseparable when we were under the same roof. He slept at the foot of my bed, trotted down the stairs after my slippered feet, waited as I fixed my coffee, and even crowded into the bathroom as I showered and blew my hair dry.What made this unusual was that Tag was generally aloof. While my mom adored her dog, she complained that he wasn’t cuddly, that he’d always give her his rump to scratch instead of his muzzle. I couldn’t help remembering that John was the same way.As the only male in our household for many years, John would often put the brakes on touchy-feely stuff. He told my mom he would give her backrubs— he on the couch, she sitting in front of him on the floor—only if she refrained from pleasurable noises. An “ooh, that feels good,” and his hands were in the air.“I’m outta here,” he would say and be off the couch, heading to the kitchen to pour himself a Coke. My practical self attributed Tag’s uncharacteristic affection to my resemblance to John. Like me, John had been fair-skinned with honey-colored hair; perhaps we even had a smell or pheromone in common. But my spiritual self believed it was more than that—that part of John’s soul was with Tag, and when Tag and I were together, John and I were too in some way.

In fact, until this trip home for the holidays, I had sometimes wondered if I should have inherited Tag. Tag’s adjustment would have been less jarring if he had stayed with me in Colorado and had an owner who was closer to John’s age and lifestyle.Yet, I knew my motivations were primarily selfish, and now I was witnessing how beautifully Mom and Tag were piecing their lives together. Mom had resumed her work as a photographer, and Tag now chased waterbirds along the shores of Lake Michigan rather than the chickens John kept on his property near the Rocky Mountains. Tag now heeled alongside Mom, though to her right side, the way my left-handed brother had purposely trained him so that he’d be away from the rifle on their occasional hunting trips. Tag’s stellar behavior evoked a pride in Mom, not only in Tag but also in her son’s fine ability with animals. Mom glimpsed John through Tag the way one sees a deceased loved one in a child who bears her likeness. As Mom and I sipped coffee in front of the Christmas tree on my first morning home, she invited me to witness a petassisted therapy program that she and Tag had become involved with over the last year. She was introduced to the program by a stranger who had remarked how well-trained Tag was.

“Yes, he is wonderful, but that credit really goes to my son,” Mom had explained. During the brief conversation that followed, the man said he volunteered with a group that helped others through the use of dogs. Then and there, Mom had resolved to sign up.

The next day, however, she’d questioned whether she had the emotional strength to work with people who had disabilities.We were grateful John’s departure from this world had been quick and peaceful. His girlfriend had smiled between sobs as she recounted that she and my brother had been goofing off on the mountain just moments before John, an expert skier, inexplicably collided with a tree, rupturing his aorta. John had, at least, not suffered—unlike those whom my mother would train Tag to assist. Despite her hesitations, Mom summoned the courage to contact the organization. “Chenny Troupe,” a cheerful woman answered. Chenny, Mom later learned, was the name of the pioneer dog of the program.

“My name is Mary Ann Alexander, and I have my son’s dog. Well, he’s my dog now,” she began.

The compassionate voice interrupted. “I know about your son,Mary Ann.My husband works with John’s father. I was at the funeral.My name is Carole Hunt.” This was an almost eerie coincidence in a city the size of Chicago. My mother’s resolve to train Tag in pet-assisted therapy was restored. Tag was hers for a reason. Maybe this was it.

When Mom received the Chenny Troupe brochure in the mail a few days later, she settled on the rug beside Tag to read it. The literature emphasized that, more than providing companionship, these therapy dogs helped with the rehabilitation of patients. The dogs needed to be not only well-trained but also gentle enough to work with children and energetic enough to engage a person with a disability. They must be patient and unbothered by wheelchairs, walkers, back braces or helmets as well as the awkward movements and vocalizations of some of the patients. Few dogs pass the rigorous obedience screening on the first try. The test date was only two weeks away. “You’ll do it, Tag,”Mom said, as she slid onto her side to lock eyes with her best friend. In a rare but increasingly frequent show of affection, Tag covered her face with kisses.

When the time came,Tag obeyed every instruction with an attentiveness that would have made John proud. Tag and my mother were invited into the program. Now, sitting in Mom’s kitchen a year later, I saw no trace of the initial butterflies she’d had, as she saddled Tag with his official work vest in preparation for tonight’s session. I, however, was nervous, even in my limited role as an observer. Then I remembered Mom commenting that Tag’s omniscient look had allayed her fears.When I saw the pure intention in his eyes, I felt my internal compass needle, haywire for over a year, regain its bearings.

Tag looked handsome, even cocky, as he leaped into the back seat to be driven to the Rehabilitation Institute of Chicago (RIC). From the front seat I turned to tell him, “You know John wants you to do this, don’t you, smart boy?” Mom’s eyes smiled—the sandbags between us long gone—as we pulled onto Lakeshore Drive. The RIC elevator door opened to a large recreation room milling with patients, therapy dogs and their owners.Mom’s preeminence in the program showed as she was swallowed by the group to answer last-minute questions before the therapy began. Eventually, all the dogs and volunteers, paired with their patients, were spread throughout the room. In one corner, a young man negotiated trading his walker for a leash, while a teenage girl pressed her dormant vocal cords into service to command a dog to sit.

For Mom and Tag, this was the last night of a six-week partnership with a seven-year-old girl named Samantha. In an automobile accident on Christmas Eve, Samantha had lost her little sister and been partially paralyzed on her right side. She was in a wheelchair and had lost much of her speech. An older sister and both parents, who had survived the wreck with minor injuries, were there to cheer Samantha on.

Sam had fallen in love with Tag the first night they worked together. Initially, Sam would pet Tag only with her left hand, until my mother, remembering her training, urged Sam to pet him with her right hand. As Sam fought to communicate with her right side, Tag nudged her hand with his wet nose. Tag’s touch made Sam giggle, evoking a gasp from her mother, who hadn’t heard her laugh since before the accident. Slowly, Sam’s hand obeyed her brain’s signal. She extended her clenched fist enough to knock on Tag’s shoulder. It was a tremendous achievement. Every Tuesday night for six weeks, Tag helped Samantha overcome her paralysis. Sam learned to uncurl her fist to accept a tennis ball and then to throw it to Tag, who retrieved it and begged for more.

Their favorite game involved Sam balancing a dog biscuit on Tag’s nose while he waited for the command to nod his head and catch the biscuit. Now, Sam’s actions with Tag were almost fluid, and she said his name clearly.

Samantha’s mother, Julie, told us that every time they got into the car, the little girl would ask,“Tag?”—hoping they were on their way to the RIC. I listened as my mother shared with Julie her story of losing her son.My mother hadn’t wanted to burden Julie with our loss. Tonight, though, as Julie presented my mother with a bouquet of flowers for all she had done, it seemed appropriate.Upon hearing about John, Julie commented, “Your son was going to be a veterinarian so he could heal animals, but now his animal heals people.”

With Christmas behind me, I boarded my flight back to Denver. As I buckled my seat belt, I noticed Tag’s straight black hairs covering my beige corduroy pants, and smiled. Brushing the hairs from my lap, I thought how Tag was with me in more ways than just his shedding coat. Tag had taught me,my mother and even Samantha’s mom Julie that there is hope after tragedy.

In the days after John’s death, I had fearfully asked Mom,“Will we ever be okay again?” She responded that she did not know how we ever could be. Yet, we are okay—due in large part to a huge-hearted black Lab with a wise old soul.

Emily Alexander Strong, who taught middle school before becoming a writer, has been published in the anthologies It's a Girl and the "Cup of Comfort"series; she and her family live in Oregon. This essay previously appeared in A Cup of Comfort for Dog Lovers (2007).